After diagnosing my problem yesterday, and upon a closer examination of the wiring diagram for my 1992, I am left wondering

Why are there no fuses to the input terminals 30 on either of these relays. That seems rather poor electrical engineering (I am an EE, as well as having about 50 years experience in DC power systems in solar, cars and boats).

I have found it usefull to install DC thermal breakers on power supply lines to relays on most of my vehicles. For instance, on my S600 (another V12) Mercedes, the vacuum pump caught fire, and I almost lost the car. The DC motor was not made to be reversible, but that didn't stop MB from placing it into service for the main vacuum pump that controls EVERYTHING. Once the brushes disintegrated and jammed the rotor, the stator overheated and caught fire. Of course it had to be placed under the rear seat, so the foam in the seat started smoldering.

It's not standard in British car electrics. Even my 1972 TVR has a main fuse, as did my TR6's and MGBs.

Any thoughts?

 

Never caused any issues in any of mine.

Never needed to look too far into the schematics, and never, ever went the path of:

"why is it so"

Its a Jaguar, not a TVR, MG, Triumph, whatever.

Mine have all done what they have been asked without fuss. Extreme conditions mainly.

The newer "Jags" in the fleet have fuses for more things than I know what to use in the damn things.
Suppose the later versions need to be "idiot proof" by comparison to the real stuff of old.

I DO NOT disagree with what you say, just that I have never re-invented the wheel on any of my Jags.

There are some "ballsy" fuses above the driver knee, and I dont have a handbook etc close at hand, but I seem to remember?? that they protected most of the "critical" stuff.

 

It is a bit odd, isn't it ? I recall briefly questioning the lack of fuses on those circuits. Then the thought passed . I'm a bit nonchalant so I've found that the mysteries of Jaguar rationale are often best met with a chuckle and a shrug.

Anyhow, I see no reason to avoid adding breakers, as you mention, if it makes you more comfortable. Doesn't seem like a bad idea but, OTOH, over the many many years I don't recall hearing of problems due to lack of circuit protection.

Cheers
DD

 

Doug, I also did the chuckle and shrug, followed by COFFEE, and a small JD.

Agreed, no harm in adding if that is what you want, as, at the end of the day, it is YOUR car.

Just looking at the X Type washers not working, oops. 2 fuses, one 20amp, one 15, and the schematics are as clear as mud at he moment, but it looks like the 20 is the main, and the 15 is the backup, WHY.?? 20 and 15 for a stand alone washer pump, DAMN, must be some serious pump tucked away somewhere, next task, WHERE.

Coffee's up, srr ya.

 

I'll probably do the mod, as I'll be sitting in the boot monday anyway putting in the main relay and relocating the mounts.

Doug: I'm hoping to be able to drive the car out to Seattle (Bremerton, actually) next June. My main sailboat is out there, so I'd love to have the Jag and the 928 there. The drives out that way are much more beautiful than here around Baltimore. And it just sounds nicer, having the car in the PNW, as opposed to mid-Atlantic.

 

You really know how to live


Cheers
DD